Re: [PATCH v4 12/23] iommufd/driver: Add iommufd_hw_queue_depend/undepend() helpers

On Thu, May 08, 2025 at 08:02:33PM -0700, Nicolin Chen wrote:

+/*

• • Helpers for IOMMU driver to build/destroy a dependency between two sibling
• • structures created by one of the allocators above
• */

+#define iommufd_hw_queue_depend(dependent, depended, member) \

• ({ \

• static_assert(__same_type(struct iommufd_hw_queue,             \
  

• 			  dependent->member));                 \
  

• static_assert(offsetof(typeof(*dependent), member.obj) == 0);  \
  

• static_assert(__same_type(struct iommufd_hw_queue,             \
  

• 			  depended->member));                  \
  

• static_assert(offsetof(typeof(*depended), member.obj) == 0);   \
  

• _iommufd_object_depend(&dependent->member.obj,                 \
  

• 		       &depended->member.obj);                 \
  

• })

This doesn't need the offsetof == 0 checks, it isn't an allocator. And you want to check that the two structs have the same type:

static_assert(__same_type(struct iommufd_hw_queue, dependent->member)); static_assert(__same_type(typeof(*dependent), *dependend));

Jason